Circuit breaker



Oct. 19, 1937. J. a. JACKSON 0 IRCUlT BREAKER Original Filed Aug. 15,1935 2 Sheets-Sheet 1 s i CJY Ta a m 5 Oct. 19, 1937.. J. G. JACKSON I2,096,547

CIRCUIT BREAKER Original Filed Aug. 15, 1935 2 Sheets-Sheet 2 22 U 9 a):/I 2a .45;

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INVENTOR J27??? 6. Jkcfisoiz vg/MW I l l I 1 I77 Y Patented Oct. 19,1937 UNITED STATES PATENT OFFICE CIRCUIT John G. Jackson,

BREAKER Detroit, Mich, assignor to Square D Company, Detroit, Mich., acorporation of Michigan Original application Au 36,247. Divided and gust15, 1935, Serial lqo.

this application June 25,

8 Claims.

This invention relates to devices for making and breaking electricalcircuits and has for its object the provision of an improved operatingmeans for an automatic electric circuit breaker.

Another object of the present invention is to provide an automaticelectric circuit breaker with an operating handle having a rotarymovement for normal separation and engagement of the cooperatingcontacts, a straight line movement to indicate overload trippedcondition, and a straight line movement for resetting the breakermechanism.

Other objects and features of the invention will be readily apparent tothose skilled in the art from the following specification and appendeddrawings illustrating certain preferred embodiments of the invention inwhich:

Figure 1 is a front elevational view of a circuit breaker according tothe present invention with both the exterior cover and the cover of thecircuit breaker proper broken away to show internal parts.

Figure 2 is a horizontal sectional view taken on the line 11-11 ofFigure 1.

Figure 3 is a vertical sectional view taken on the line III-III ofFigure 1.

Figure 4 is a fragmentary sectional view showing the breaker mechanismin the automatic tripped position.

Figure 5 is a fragmentary sectional view showing the breaker mechanismin the resetting position.

This application is a division of application Serial No. 36247, filedAugust 15, 1935, for Circuit breakers.

The circuit breaker illustrated in the drawings comprises an outsideenclosing box I having a cover 2 hingedly mounted thereon. Within thisbox is disposed a sealable multi-circuit circuit breaker comprised of aninsulating base 3 and a metal cover 4. The cover 4 is adapted to besealably attached to the base 3 by means of rivets 5. The cover 4extends across the width of the box and to one side there is riveted orotherwise attached a hinge 6 which is bolted to the side walls of thebox as at I. The opposite side of the metal cover 4 is provided with aflange 8 carrying a bolt 9 adapted to be 'received within a slot H inthe box wall tosecure the cover 4 and breaker mechanisms within the boxI. The cover 4 is provided with a plurality of openings through whichextend the push button handles l2 for operating the breaker mechanisms.The box cover 2 is provided with a generally central opening whichclosely receives a slightly raised portion l3 in the cover 4 so that theoperating push button handles I 2 extend to the box exterior. The hingedmounting of the metal cover 4 permits the circuit breaker to be swung tothe exterior of the box to facilitate pulling in and connecting of thecircuit wires. To then secure the circuit breaker within the boxinterior it is swung back to its interior position with the bolt 9received within the slot ll whereupon tightening of the bolt 9 willsecure the circuit breaker in position.

The individual circuit breaker mechanisms comprise a movable contact barcarrying a contact tip l5 adapted to engage with a common stationarycontact l6 which is rigidly secured to the base by means 01' a bolt II.The free end of the contact bar I4 is normally latched in the positionshown at the bottom of Figure 2 by the bimetallic current responsivemember l8. The bimetallic strip i8 is rigidly welded or otherwisesecured to an arm l9 centrally punched or otherwise spaced from the mainpart of a connector 2| which is rigidly secured to the base by means ofrivet 22. The side arms thus formed at the end of the connector 2! arebent over as at 23 and within the space formed between the connecter 2|,the bent-over portions 23 and the arm I9 is disposed a block 24 throughwhich is threaded a stud 25 bearing against the free end of arm l9 andthus serving as an adjusting or calibrating means for the bimetallicstrip. Within the rivet 22 is threaded a stud 26 forming the terminalfor the breaker. A flexible lead 21 connects the free end of bimetallicstrip it with the contact bar l4 adjacent to a pivot point thereof to behereinafter described. The por tion of the bar l4 between the lead 21and the bimetallic strip I8 is provided with holes or otherwise reducedin cross-section to increase its resistance and lessen the currentpassing directly from the bimetal to the bar through their latchingengagement.

A compression spring 28 is provided between the base 3 and the contactbar l4 and acts to bias the bar away from the main body of the base.This spring is located closer to the contact tip is than to the latchingend of the bar to provide a high contact pressure without undulyincreasing the pressure between the bar and the bimetallic latchingmember.

For operating the contact bar l4 there is provided a generally U-shapedmember 29 having legs of different lengths. The longer leg of the member29 is provided with a slot 3| in which the contact bar is disposed. Theupper portion of the bar withinthis slot is provided with a notch 32engaging the end of the slot and serving to restrain the bar fromlongitudinal movement as well as to provide a pivot point for movementof the bar to automatic trip and reset positions. The short leg of theU-shaped member is also slotted to receive the contact bar in overloadposition as more particularly shown in Figure 3.

The base 3 is provided with a plurality of upstanding walls 33 providedwith slots receiving the bar l4 and with suitable projections forholding and guiding the member 29 in its reciprocal movement.

In front of the operating member 29 is provided an L-shaped push buttonhandle l2 having its leg extending through the cover 4. The base of thehandle I2 is provided with a groove 34 mounted over a projection 35 onthe closed end of the member 29. A small compression spring 36 isdisposed within the handle base and bears against the under side ofcover 4 in position to normally maintain the upper side of the base adefinite distance from the cover. The ends of the base of the L areprovided with smooth curves to facilitate rotation of the push buttonhandle about an axis at right angles to its direction of straight linemotion. The leg and the adjacent curved portion of the L-shaped handleare of a size to fit snugly within the opening in the cover 4. Theremaining portion of the base as at 31 is enlarged and in the rotatedposition of the handle forms flanges bearing against the edges of theopening. A colored ring 38 may be placed on the outwardly projecting legof the handle for a purpose to be hereinafter described.

The operation of mechanism will now be described in detail.

The mechanism shown at the bottom of Figure 3 is in the normal closedoperating position. In the circuit breaker at the top of Figure 3 thehandle I2 has been rotated 90 degrees so that the end of the base of thehandle now bears upon the closed end of the member 29 with the enlargedportion 31 forced against the under side of cover 4 by spring 28. Thisin eiTect forms a simple toggle and the parts are maintained in thisposition. As the length of the base of the handle from enlargement ofportion 31 to the end is greater than the distance between'member 29 andcover 4 in the normal operating position, the member 29 has been movedtoward the base moving the contact bar l4 by engagement of the end-ofslot 3| with notch 32 in the bar. In this movement the bar pivots aboutits engagement with the bimetallic member l8 and assumes the positionshown in the upper circuit breaker in Figure 3 which is the manual offposition. In again closing the circuit through the breaker it is onlynecessary to flip the handle back 90 to the position shown in the lowercircuit breaker in Figure 3 whereupon the contact bar I4 is movedupwardly to the position therein shown under action of the compressionspring 28. When an overload is passed through the circuit breaker itbecomes heated and is deflected away from the contact bar l4 thusreleasing the end thereof and permitting this end to move away from themain body of the base 3. This movement of the contact bar I4 is causedby the compression spring 28 and the bar l4 moves about the engagementof the notch 32 a with the top of the slot 3| into the position shown inFigure 4. The upward movement of the contact bar is restrained only byits engagement this single circuit breaker with member 29 which pressesagainst the base of the push button handle l2. As the spring 36 isrelatively weak as compared with the spring 28, the base of the handlewill be moved against the under side of the cover 4 and the overloadtripped condition of the breaker will be indicated by the extendedposition of the arm of the handle which brings the colored ring 38 intoview above the cover. To reset the breaker mechanism it is necessaryonly to press inwardly upon the push button handle l2. In the extremeinward movement of the handle, the parts assume the reset position shownin Figure 5 with the end of the contact bar again in a position to haveits upward movement restrained by the bimetallic member 3 and with thecontact tip separated from the stationary contact Hi. When the handle isreleased it will be moved outwardly tothe position of the lower breakerin Figure 3 under action of spring 29 and the movable contact l5 will beengaged with the stationary contact. By this method of resetting it isobviously impossible to prevent the automatic tripping of the breaker byholding the operating handle as the contacts are not engaged to closethe circuit until the operating handle moves to its normal operatingposition. If the push button handle is pushed inwardly and held therethe contacts simply remain separated as shown in Figure 4. If theoperating handle should be held in its nonindicating position as shownin the lower portion of Figure 2 the contacts will separate to the sameextent although the now free end of the contact bar will not move to itsfull upward position until the handle is released. However, the contactcarrying end of the bar will still move against the main body of thebase and separate the contacts.

The connection of the flexible lead 21 to an intermediate point on thebar l4 serves two functions as it not only lessens the movement of thelead, but also by by-passing a length of the bar places its resistancein the circuit through the latching engagement. This resistance may beincreased, as shown, by reducing the cross section of the bar or may beincreased in any other manner as by the interposition of insulation or ahighly resistant material.

Guides or stops l8 and 28 are provided at the ends of the bar l4. Theselimit and guide the longitudinal movement of the bar. The limiting stopl8 also provides a positive pivot point for the bar in its movement toreset position. The stop 20 also prevents the bar moving with thebimetal where there is play at the notch 32.

In the multi-circuit form of circuit breaker illustrated, a plurality ofcircuit breaker mechanisms are mounted upon base 3. In the specificexample herein disclosed the base is provided with a generally centraldividing wall 39 which divides the mechanism into two duplicate andelectrically separate parts each of which may be regarded as amulti-circuit circuit breaker.

Describing now the multi-circuit circuit breaker shown at one side ofthe dividing wall 39, there is provided a central wall 4| having acutout portion 42 in which is maintained a stationary contact plate IS.The bolt l'l projects upwardly through the central portion-of the wall4! and rigidly secures the contact plate to the base. The openingthrough which the bolt I'I projects may then be waxed to provideinsulation.

Between the contact l6 and the supporting portion of the wall 4| isdisposed an insulating strip 43' having cutout portions through whichthe movable contacts project to engage the contact IS. The insulatingstrip 43 projects beyond the contact I6 on both sides of the wall 4| tothe member 29 and in combination with the walls of the base forms an arcchamber. This arrangement permits the discharge of gas from therupturing of a single breaker into the space occupied by the multiplegroup of breakers thus rendering less necessary any important dischargevent to the outer air. The central wall 4| may be integral with certainof the walls 33 and in this construction the walls 33 may be consideredto form projections upon the side walls of the base and the wall 4|rather than as unitary walls slotted to receive the member |4. I'he endsof the breaker are provided with fibre shields 45 extending between thebase 3 and the cover 4 and scalable therewith by rivet 5.

While certain preferred embodiments of the invention have beenspecifically disclosed, it is understood that the invention is notlimited thereto as many variations will be readily apparent to thoseskilled in the art and the invention is to be given its broadestpossible interpretation within the terms of the following claims.

What is claimed is:

1. In an automatic electric circuit breaker, stat onary and movablecontacts, automatic means for separating said contacts in response tooverload, and a manually operable push button for resetting saidbreaker, said push button rotating about an axis at right angles to itsdirection of reciprocation to effect manual separation of said contacts.

2. In an automatic electric circuit breaker, relatively movablecontacts, automatic means for separating said contacts in response tooverload, a manually operable push button handle for said circuitbreaker, said handle having a straight line movement to indicateoverload trip, a straight line movement to reset the breaker mechanismand a rotary movement about an axis at right angles to its direction ofstraight line movement to effect manual separation of said contacts.

3. In an automatic electric circuit breaker, stationary and movablecontacts, automatic means for separating said contacts in response tooverload, a manually operable handle for separating said contacts andfor resetting said breaker after an automatic separation, said handlehaving a transverse rotary camming movement to separate said contactsand a straight line reciprocatory movement to reset said breaker.

4. In an automatic electric circuit breaker, relat vely movablecontacts, automatic means for separating said contacts in response tooverload, and a manually operable L-shaped push button handle for saidcircuit breaker, an enclosure for said circuit breaker through whichsaid handle projects, the base of the L within the enclosure being widerthan said opening whereby when the handle is rotated 90 about an axis atright angles to its push button movement a stable camming position isattained.

5. In an automatic electric circuit breaker, relatively movablecontacts, automatic means for separating said contacts in response tooverload, and a manually operable L-shaped push button handle for saidcircuit breaker, an enclosure for said circuit breaker through whichsaid handle projects, the base of the L within the enclosure being widerthan said opening whereby when the handle is rotated 90 about an axis atright angles to its push button movement a stable camming position isattained, and curved surfaces at the end of the base and at the junctionof the base and arm of the L to facilitate the rotating movement.

6. In an automatic electric circuit breaker, stationary and movablecontacts, automatic means for moving said movable contact to separatedposition in response to overload, a manually operable L-shaped pushbutton handle, a member intermediate said handle and movable contact,said member having a flat surface engaging the base of said L, a lug onsaid face, a groove in said base receiving said lug, said lug and grooveguiding the rotation of said handle about an axis at right angles to itspush button movement.

7. In an automatic electric circuit breaker, relatively movablecontacts, automatic means for separating said contacts in response tooverload, an operating handle for manually separating said contacts andfor resetting said breaker after an automatic separation, an enclosurefor said circuit breaker through which said handle projects, saidhandlehaving a definite position with relation to the enclosure when thecontacts are manually separated, and spring means normally maintainingsaid handle in a second definite position with relation to the enclosurewhen said contacts are engaged, said automatic means overcoming thespring means to move the handle to a definite position with relation tothe enclosure to indicate the overload tripped position of the breaker.

8. In an automatic electric circuit breaker, a base, relatively movablecontacts supported by said base, automatic means for separating saidcontacts in response to overload supported by said opening contacts.

JOHN G. JACKSON.

